1. Field of the Invention
This invention relates generally to hydraulic hose fittings. More particularly, it relates to O-ring face seal fittings. Specifically, it relates to improved female portions of O-ring seal flat faced terminations, for tube and hose fittings.
2. Description of the Prior Art
O-ring seal flat face fittings are known in the art. Typically, the female portion forms part of a separate fitting or connector that connects a hydraulic hose to a machine, equipment, or fixture or is fixed upon or directly a part of a tube that connects the tube to a machine, equipment, or fixture.
In one form of the female portion, the end of a tube is flared to the point of presenting a flat-faced annulus at the tube""s open end. The annulus has an inside diameter substantially equal to the inside diameter of the tube from which the annulus is created. The annulus is supported by a collar or sleeve that is brazed, welded, pressed or otherwise affixed upon the tube in a manner well known in the art against the annulus opposite of the flat end facing away from the tube(see FIG. 1).
For connecting the female portion to the male portion, a nut having internal threads covering a portion of its interior and having a reduced diameter unthreaded portion, or shoulder, covering the remaining portion of the nut fits over the tube and about the annulus and the collar or sleeve. The male portion has an O-ring face including a groove for housing an O-ring, and an O-ring therein, and external threads proximate the face having the O-ring. Upon connection, the nut is threaded over the external threads of the male portion. The threading action reduces the distance between the O-ring face and the shoulder of the nut. As the shoulder""s inside diameter is less than the outside diameter of at least a portion of the supporting collar or sleeve, the axial restraining portion (enumerated 29 in FIGS. 1 and 2), the annulus and the O-ring face are brought into sealing contact.
In another form of female portion of O-ring face seal fitting, a sleeve which includes a flat end face is brazed, welded or otherwise affixed to the end of the tube. The sleeve has an overall outside shape substantially similar to the combination of the annulus and the support, of the previously described form (see FIG. 2).
Both of these forms have significant disadvantages in both production and operation. First, they both require a separate sleeve to be produced and affixed to the tube, adding to the cost and complexity of producing the female portion of the O-ring seal flat face fitting. Second, this style of fitting has a tendency to loosen, leak, and fail under certain conditions. When the female portion is twisted in relation to the male portion of the fitting, such as under the influences of impacts upon the fitting or vibration, the friction between the female portion and the nut can cause the nut to turn and to loosen. This situation is predominantly related to fittings where the tube is bent as depicted in FIG. 4. In this configuration, side impacts to the fitting creates a moment about the axis of where the male and female portions connect. This, in turn, causes a torque upon the female portion relative to the male portion. However, opportunities for twisting can present themselves where the tube is not bent.
Accordingly, there is a continuing need for an O-ring seal flat faced fitting, including a female portion, of simplified construction that has an improved resistance to leakage brought on by loosening caused by twisting of the tube.
The present invention has as an object the provision of an O-ring seal flat face fitting, including a female portion, of simplified construction.
The present invention has the further object of the provision of an O-ring seal flat face fitting, including a female portion, having improved resistance to leakage brought on by loosening caused by twisting or vibration of the tube.
The present invention is an improved O-ring seal flat face fitting of the type having a male portion including an O-ring, and a female portion having a tube with an inside diameter, an extended peripheral limit having a diameter corresponding to said inside diameter, a nut, and a joinder portion. It is improved by the joinder portion including a void having a portion extending radially beyond the extended peripheral limit.